Being almost a chronograph "Ace" (I've shot 3, two more to go to get "ace" status) I can tell you what not to do.
With my first Chronograpy, a Pact that I tried to make work for five years, I finally (intentionally) put three 9mm rounds through the skyscreens. It worked just as well afterward as it did before. It would only show accurate data early in the morning or late in the evening when there was no sunlight. Sometimes heavy cloud cover would work. I tried all the usual things to make it work but no luck.
The second- a ShootingChrony. Worked quite well until I shot the LED screen with a shotgun wad. I was plenty high enough for the 12 gauge slug to clear the skyscreens but I forgot all about the wad. Now I put a small section of 2 X 4 in frone of the skyscreen before testing shotgun loads. You don't need this precaution with rifles or pistols.
The third- the above ShootingChrony after it was repaired by the factory. I was zeroing a scoped rifle and low and behold I was not holding high enough when viewing through the scope. The bullet just creased the metal above the skyscreens but it still works well. That shot really messed up my group however.
So in summary- shoot high, watch the shotgun wads and don't be surprised if your loads chrono below what you thought they would be. Every reloader needs a chrono to shoot to their full potential.
Merry Christmas- oldandslow